The present invention belongs to the technical fields of silver halide photographic emulsion and method for chemical sensitization thereof, in particular, the technical fields of silver halide photographic emulsion of which sensitivity, fog and storability are improved by controlled chalcogen sensitization and method for chemical sensitization of such an emulsion.
In silver halide photographic light-sensitive materials, silver halide emulsions subjected to chemical sensitization using various kinds of chemical substances are generally used in order to obtain desired sensitivity, gradation and so forth. As typical methods for that purpose, there are known various sensitization techniques including chalcogen sensitization such as sulfur sensitization, selenium sensitization and tellurium sensitization, noble metal sensitization such as gold sensitization, reduction sensitization using a reducing agent and so forth, which are used each alone or in combination. In recent years, the requirements for higher sensitivity, superior granularity, gradation or high sharpness, good storability, quick development with accelerated progress of development and so forth for silver halide photographic light-sensitive materials are increasingly become severer.
Among the aforementioned techniques, the chalcogen sensitization is a technique indispensable to high sensitivity silver halide photographic emulsions, and various researches have been conducted for many years aiming at further higher sensitivity. However, higher sensitivity invites, in particular, increase of fog, and long term storage always invites sensitivity fluctuation and increase of fog. Therefore, there have been strongly desired ameliorations of these problems. As for these problems, there has hitherto been attempted to solve them by addition of antifoggants or stabilizers, improvement of chalcogen sensitizers and so forth. However, these attempts have been made mainly on trial and error basis to provide improvements, and any universal technique has not been established. On the other hand, although noble metal sensitization that utilizes a transition metal for chemical sensitization is known for many years, any method of realizing effective action of chemical sensitization with a transition metal by combination with chalcogen sensitization has not been known at all.
The present invention was accomplished in view of all the aforementioned problems, and the first object of the present invention is to provide a silver halide emulsion showing high sensitivity and low fog. The second object of the present invention is to provide a silver halide emulsion showing superior storability. The third object of the present invention is to provide a method for chemical sensitization that provides a silver halide emulsion showing high sensitivity without degrading fog and storability.
In order to achieve the aforementioned objects, the inventor of the present invention paid attention to the relationship between crystallinity of silver chalcogenide or gold silver chalcogenide produced by chalcogen sensitization and characteristics of the obtained emulsion, and conducted various researches on the relationship. As a result, he found that, if at least a part of silver chalcogenide or gold silver chalcogenide produced by chalcogen sensitization is amorphous, an emulsion showing superior characteristics could be obtained, and accomplished the present invention based on this finding.
In order to achieve the aforementioned objects, the silver halide emulsion of the present invention is a silver halide emulsion containing silver chalcogenide or gold silver chalcogenide produced by chemical sensitization, wherein at least a part of the silver chalcogenide or gold silver chalcogenide is amorphous.
In the present invention, intensity of a maximum X-ray diffraction peak of the silver chalcogenide or gold silver chalcogenide is preferably xc2xd or less of intensity of a maximum X-ray diffraction peak of silver chalcogenide or gold silver chalcogenide that is not amorphized.
Further, in order to achieve the aforementioned objects, the method for chemical sensitization of a silver halide emulsion of the present invention is a method for chemical sensitization of a silver halide emulsion comprising a sensitization step of subjecting the silver halide emulsion to chemical sensitization with a chalcogen compound or a chalcogen compound and a gold compound to produce silver chalcogenide or gold silver chalcogenide, wherein the chemical sensitization is performed under such conditions that at least a part of the silver chalcogenide or gold silver chalcogenide produced in the sensitization step should be amorphized.
In the chemical sensitization method of the present invention, the chemical sensitization is preferably performed in the presence of transition metal ions of at least one metal selected from the metals of Group IB, Group IIB, Group VIA, Group VIIA and Group VIII. Further, in the chemical sensitization method of the present invention, the maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained for a standard model as defined in the following (a) (Intensity A) and the maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained by applying the chemical sensitization conditions of the chemical sensitization step to a simplified model as defined in the following (b) (Intensity B) preferably satisfy the relational equation defined in the following (c):
(a) silver chalcogenide or gold silver chalcogenide produced by mixing 20 mL of 0.01 mol/L silver nitrate aqueous solution, 20 mL of 0.01 mol/L solution of the chalcogen compound in water or an alcohol and, when a gold compound is also used in the chemical sensitization, 0.01 mol/L solution of the gold compound in water or an alcohol in such an amount that the gold compound and the chalcogen compound should exist in the same molar ratio as that used for the chemical sensitization at the temperature used for the chemical sensitization,
(b) silver chalcogenide or gold silver chalcogenide produced by mixing the chalcogen compound or the chalcogen compound and the gold compound with 20 mL of 0.01 mol/L silver nitrate aqueous solution under the same conditions as those of the chemical sensitization, except that the silver halide emulsion does not exist, the chalcogen compound is added as 0.01 mol/L solution in water or an alcohol and the other additives are added in such amounts that molar ratios of the additives with respect to the chalcogen compound should be the same as those used for the chemical sensitization,
(c) B/Axe2x89xa6xc2xd.
According to the present invention, there can be provided a silver halide emulsion showing high sensitivity, low fog and superior storability. According to the present invention, there can also be provided a method for chemical sensitization of a silver halide emulsion, which provides a silver halide emulsion showing high sensitivity while obviating increase of fog and degradation of storability.
The present invention will be explained in detail hereafter. In the following description, ranges indicated with xe2x80x9c-xe2x80x9d mean ranges including the numerical values before and after xe2x80x9c-xe2x80x9d as the minimum and maximum values.
The silver halide emulsion of the present invention contains silver chalcogenide or gold silver chalcogenide produced by chemical sensitization. It is sufficient that the silver halide emulsion of the present invention be chemically sensitized by using at least a chalcogen compound (henceforth referred to as xe2x80x9cchalcogen sensitizationxe2x80x9d), and it may be chemically sensitized by a combination of chalcogen sensitization and another type of sensitization. As the other type of sensitization, gold sensitization is preferred. When chalcogen sensitization and gold sensitization are used in combination, gold silver chalcogenide is formed by chalcogen sensitization. The chalcogen sensitization include sulfur sensitization, selenium sensitization, tellurium sensitization and sensitization by a combination of two or more of them.
For the sulfur sensitization, labile sulfur compounds are used as sulfur sensitizers. For example, there can be used labile sulfur compounds described in P. Grafkides, Chimie et Physique Photographique, 5th Ed., Paul Montel, 1987, Research Disclosure, Vol. 307, No. 307105 and so forth. The labile sulfur compounds used herein are known sulfur compounds, for example, thiosulfates (e.g., hypo), thioureas (e.g., diphenyithiourea, triethylthiourea, N-ethyl-Nxe2x80x2-(4-methyl-2-thiazolyl)thiourea, carboxymethyltrimethylthiourea), thioamides (e.g., thioacetamide), rhodanines (e.g., diethylrhodanine, 5-benzylidene-N-ethylrhodanine), phosphine sulfides (e.g., trimethyiphosphine sulfide), thiohydantoins, 4-oxo-oxazolidine-2-thiones, di- or poly-sulfides (e.g., dimorpholine disulfide, cysteine, hexathiocane-thione), mercapto compounds (e.g., cysteine), polythionates, elemental sulfur and so forth as well as active gelatin. Particularly preferred are thiosulfates, thioureas, phosphine sulfides and rhodanines.
For selenium sensitization, labile selenium compounds are used as selenium sensitizers. For example, there can be used selenium compounds disclosed in Japanese Patent Publication (Kokoku, referred to as JP-B hereinafter) No. 43-13489, JP-B-44-15748, Japanese Patent Laid-open Publication (Kokai, referred to as JP-A hereinafter) No. 4-25832, JP-A-4-109340, JP-A-4-271341, JP-A-5-40324, JP-A-5-11385, JP-A-6-051415, JP-A-6-175258, JP-A-6-180478, JP-A-6-208186, JP-A-6-208184, JP-A-6-317867, JP-A-7-092599, JP-A-7-098483, JP-A-07-140579 and so forth. Specifically, there can be used colloidal metal selenium, selenoureas (e.g., N,N-dimethylselenourea, trifluoromethylcarbonyltrimethylselenourea, acetyltrimethylselenourea), selenoamides (e.g., selenoamides, selenoacetamide, N,N-diethylphenylselenoamide), phosphine selenides (e.g., triphenylphosphine selenide, pentafluorophenyltriphenylphosphine selenide), selenophosphates (e.g., tri-p-tolylselenophosphate, tri-n-butylselenophosphate), seleno ketones (e.g., selenobenzophenone), isoselenocyanates, selenocarboxylic acids, seleno esters, diacyl selenides and so forth. In addition, non-labile selenium compounds disclosed in JP-B-46-4553 and JP-B-52-34492 such as selenious acid, selenocyanates (e.g., potassium selenocyanate), selenazoles and selenides can also be used. Particularly preferred are phosphine selenides, selenoureas, seleno esters and selenocyanates.
For the tellurium sensitization, labile tellurium compounds are used as tellurium sensitizers. For example, there can be used labile tellurium compounds described in JP-A-4-224595, JP-A-4-271341, JP-A-4-333043, JP-A-5-303157, JP-A-6-27573, JP-A-6-175258, JP-A-6-180478, JP-A-6-208186, JP-A-6-208184, JP-A-6-317867, JP-A-7-140579 and so forth. Specifically, there can be used phosphine tellurides (e.g., butyldiisopropylphosphine telluride, tributylphosphine telluride, ethoxydiphenylphosphine telluride), diacyl (di)tellurides (e.g., bis(diphenylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) ditelluride, bis (N-phenyl-N-methylcarbamoyl) telluride, bis(N-phenyl-N-benzylcarbamoyl) telluride, bis(ethoxycarbonyl) telluride, telluroureas (e.g., N,Nxe2x80x2-dimethylethylenetellurourea, N,N-diphenylethylenetellurourea), telluroamides, telluro esters and so forth. Particularly preferred are diacyl (di)tellurides and phosphine tellurides.
When the aforementioned chalcogen sensitization is used in combination with gold sensitization, a silver halide emulsion can be made show higher sensitivity, lower fog and more improved storability.
As gold sensitizers, there can be used the gold salts described in P. Grafkides, Chimie et Physique Photographique (Paul Montel, 1987, 5th edition), Research Disclosure, vol. 307, No. 307105 and so forth.
Specifically, besides chloroauric acid, potassium chloroaurate and potassium auriothiocyanate, there can be used gold compounds described in U.S. Pat. No. 2,642,361 (gold sulfides, gold selenides etc.), U.S. Pat. No. 3,503,479 (gold thiolates having a water-soluble group etc.), U.S. Pat. No. 5,049,484 (bis(methylhydantoinate) gold complexes etc.), U.S. Pat. No. 5,049,485 (mesoionic thiolate gold complexes, e.g., 1,4,5-trimethyl-1,2,4-triazolium-3-thiolate gold complex etc.), U.S. Pat. Nos. 5,252,455 and 5,391,727 (large ring heterocyclic gold complexes), U.S. Pat. Nos. 5,620,481, 5,700,631, 5,759,760, 5,759,761, 5,912,111, 5,912,112, 5,939,245, JP-A-1-147537, JP-A-8-69074, JP-A-8-69075, JP-A-9-269554, JP-B-45-29274, German Patent Nos. DD-264524A, DD-264525A, DD-265474A, DD-298321A, JP-A-2001-75214, JP-A-2001-75215, JP-A-2001-75216, JP-A-2001-75217, JP-A-2001-75218 and so forth.
In the present invention, the silver halide emulsion is preferably chemically sensitized by a combination of gold sensitization and chalcogen sensitization selected from sulfur sensitization, selenium sensitization, tellurium sensitization, sulfur selenium sensitization, sulfur tellurium sensitization and sulfur selenium tellurium sensitization.
Although the preferred range of the amount of the chemical sensitizer used in the present invention may vary depending on the silver halide grains used, chemical sensitization conditions used and so forth, it is usually about 10xe2x88x928 to 10xe2x88x922 mol, preferably about 10xe2x88x927 to 10xe2x88x923 mol, per one mole of silver halide.
Although the conditions of the chemical sensitization are not particularly limited in the present invention, pAg is preferably 6-11, more preferably 7-10, and pH is preferably 4-10, more preferably 5-8. The temperature for the chemical sensitization is preferably 45-95xc2x0 C., more preferably 45-85xc2x0 C.
The silver halide emulsion of the present invention is characterized in that at least a part of the silver chalcogenide or gold silver chalcogenide produced on the silver halide is amorphous. Preferably, a half or more, more preferably xc2xe or more, of the silver chalcogenide or gold silver chalcogenide is amorphous, and all the silver chalcogenide or gold silver chalcogenide may be amorphous. Whether the silver chalcogenide or the like produced by the chemical sensitization is amorphous or not can be usually confirmed by diffraction, particularly simply, by X-ray diffraction. X-Ray diffraction measured for crystalline silver chalcogenide or gold silver chalcogenide shows a maximum peak at a specific 2xcex8 depending on its crystal system. On the other hand, X-ray diffraction of amorphous silver chalcogenide or gold silver chalcogenide does not show any peak peculiar to the crystal system. Therefore, amorphization of the produced silver chalcogenide or gold silver chalcogenide can be confirmed by measuring its X-ray diffraction and tracing intensity of a maximum peak peculiar to the corresponding crystal system, and a ratio of amorphized silver chalcogenide or gold silver chalcogenide can be estimated by calculating a reduction ratio of the peak intensity.
However, since the sensitization centers formed on the silver halide grains by the chemical sensitization (namely, silver chalcogenide or gold silver chalcogenide) actually have a small size or are formed in only a small amount, it is often difficult to determine whether the silver chalcogenide or gold silver chalcogenide has been amorphized or not by tracing the maximum peak intensity in X-ray diffraction as described above. In such a case, amorphization of silver chalcogenide or the like in an actual system can be determined by similarly performing the chemical sensitization in a model simplifying the system of interest and confirming reduction of X-ray diffraction peak intensity of the produced silver chalcogenide and gold silver chalcogenide.
As the method for determining whether the silver chalcogenide or the like produced by the chemical sensitization is amorphous or not using a simplified model based on X-ray diffraction, there can be mentioned a method of comparing intensity of a maximum X-ray diffraction peak obtained for silver chalcogenide or gold silver chalcogenide formed in a model that simplify the actual chemical sensitization with intensity of a maximum X-ray diffraction peak as a standard obtained for silver chalcogenide or gold silver chalcogenide formed by simply mixing a solution of a chalcogen sensitizer or a solution containing a chalcogen sensitizer and a gold sensitizer with a silver nitrate solution to know degree of the amorphization. Usually, if an aqueous solution containing a chalcogen compound used as a chalcogen sensitizer or an aqueous solution of a chalcogen compound used as a chalcogen sensitizer and a gold compound used as a gold sensitizer and an aqueous solution of silver nitrate are simply mixed, crystalline silver chalcogenide or gold silver chalcogenide is produced. Therefore, it can be presumed that the intensity of X-ray diffraction peak shown by the latter sample should correspond to intensity of a peak observed when the produced silver chalcogenide or gold silver chalcogenide is substantially 100% crystalline. On the other hand, as for the former sample, since at least a part of the produced silver chalcogenide or gold silver chalcogenide is amorphized, the intensity of X-ray diffraction peak shown by the former sample is reduced according to the ratio of amorphization. Therefore, by comparing the intensities of X-ray diffraction peaks of the former and the latter, the degree of amorphization of the produced silver chalcogenide or gold silver chalcogenide can be quantitatively determined, and thereby the degree of amorphization in the actual system can be presumed.
Specifically, degree of amorphization in an actual system can be presumed by comparing Intensity A of a maximum X-ray diffraction peak of silver chalcogenide or gold silver chalcogenide obtained for the following the standard model (a) with Intensity B of a maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained by applying the conditions of the actual chemical sensitization to a simplified model as defined in the following (b).
(a) silver chalcogenide or gold silver chalcogenide produced by mixing 20 mL of 0.01 mol/L silver nitrate aqueous solution, 20 mL of 0.01 mol/L solution of the chalcogen compound in water or an alcohol and, when a gold compound is also used in the chemical sensitization, 0.01 mol/L solution of the gold compound in water or an alcohol in such an amount that the gold compound and the chalcogen compound should exist in the same molar ratio as that used for the chemical sensitization at the temperature used for the chemical sensitization,
(b) silver chalcogenide or gold silver chalcogenide produced by mixing the chalcogen compound or the chalcogen compound and the gold compound with 20 mL of 0.01 mol/L silver nitrate aqueous solution under the same conditions as those of the chemical sensitization, except that the silver halide emulsion does not exist, the chalcogen compound is added as 0.01 mol/L solution in water or an alcohol and the other additives are added in such amounts that molar ratios of the additives with respect to the chalcogen compound should be the same molar ratios as those used for the chemical sensitization.
In the standard model (a), the same chalcogen compound and gold compound as the chalcogen compound used as a chalcogen sensitizer and the gold compound used as a gold sensitizer in the simplified model (b) for comparison. As described above, when amorphization is determined for chemical sensitization also utilizing a gold compound, 0.01 mol/L solution of the gold compound in water or an alcohol is added in such an amount that the same molar ratio of the gold compound and the chalcogen compound as that used in the chemical sensitization should be obtained. Further, the chemical sensitization conditions used for the simplified model (b) are those affecting the amorphization, and include, for example, concentration ratio of the chalcogen compound and the gold compound, addition conditions of sensitizers (addition time, addition temperature etc.), use or disuse of addition of amorphizing agent, which will be described later, and addition conditions of the same (addition time, addition temperature etc.) and so forth. In the simplified model (b), although concentrations themselves of the sensitizer and other additives may differ from those of the chemical sensitization conditions of the actual system, concentration ratios (molar ratios) of the components (gold compound, amorphizing agent, other additives) with respect to the chalcogen compound should be the same as those of the chemical sensitization conditions. Further, the additives may be added at such addition time that relative addition time lags with respect to the addition of the chalcogen compound should be the same as those used as the chemical sensitization conditions. Furthermore, even when a gold compound is added before addition of a chalcogen compound in an actual chemical sensitization (e.g., a case where a gold salt other than gold silver chalcogenide deposits etc.), the gold compound may be added after the addition of the chalcogen compound. Further, various materials contained in a system in an actual sensitization process may be omitted in the simplified model (b), if the materials do not affect the amorphization of the silver chalcogenide or gold silver chalcogenide to be produced. In the standard model (a) and the simplified model (b), the solvent of the solution of chalcogen compound is a solvent containing water as a main component and prepared optionally with addition of an alcohol such as methanol depending on solubility of the sensitizer. On the other hand, the solvent of the solution of the gold compound is the same solvent as the solvent of the chalcogen compound in the standard model (a), and in the simplified model (b), when the kind of solvent affects the amorphization, the solvent used for the actual chemical sensitization is used.
As a specific example, an evaluation method used when irradiation of Ka ray of copper is used will be described. When a sulfur sensitizer is used, precipitates produced in the standard model (a) consist of monoclinic silver sulfide, and the maximum peak is observed for a (121) plane at 2xcex8=34xc2x0. When a selenium sensitizer is used, precipitates produced in the standard model (a) consist of monoclinic silver selenide, and the maximum peak is observed for a (121) plane at 2xcex8=33xc2x0. When a tellurium sensitizer is used, precipitates produced in the standard model (a) consist of cubic silver telluride, and the maximum peak is observed for a (501) plane at 2xcex8=41xc2x0. These are used as standards of diffraction peak of crystalline silver chalcogenide. Intensity of the same peak as the above can be measured for a sample chemically sensitized by using amorphization conditions in the simplified model (b) and compared with the standards mentioned above to confirm presence or absence of amorphization or quantitatively confirm degree of the amorphization.
As also for amorphization of chalcogen sensitization centers obtained by using gold sensitization in combination, degree of the amorphization can similarly be determined by, as described above, adding an aqueous solution of silver nitrate at the aforementioned concentration to a solution containing a chalcogen sensitizer, gold sensitizer and, e.g., amorphizing agent under the same conditions as those of the actual chemical sensitization, and measuring X-ray diffraction of the produced precipitates. Further, as also for amorphization of sulfur selenium sensitization centers, degree of the amorphization can similarly be determined by adding an aqueous solution of silver nitrate at the aforementioned concentration to a solution obtained by mixing a sulfur sensitizer and selenium sensitizer and adding, e.g., amorphizing agent under the same conditions as those of the actual chemical sensitization, and measuring X-ray diffraction of the produced precipitates. As for sulfur tellurium sensitization centers, sulfur selenium tellurium sensitization centers and those obtained by using any of these sensitizations with gold sensitization, amorphization can be determined similarly.
As for the silver halide emulsion of the present invention, the ratio of the maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained for the aforementioned simplified model (b), Intensity B, to the maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained for the aforementioned standard model (a), Intensity A, i.e., B/A, is preferably xc2xd or less, more preferably xc2xc or less, particularly preferably xe2x85x9 or less.
The silver halide emulsion of the present invention is prepared through a sensitization process in which the silver halide is sensitized with at least a chalcogen compound. Further, the silver halide emulsion of the present invention can be prepared with such conditions that at least a part of sensitization centers produced by the aforementioned sensitization process (namely, silver chalcogenide or gold silver chalcogenide) should be amorphized. The conditions for amorphizing the silver chalcogenide or the like used herein may be each of conditions including type of amorphizing agent, addition time (timing) of sensitizer and/or amorphizing agent, concentration ratio of the chalcogen sensitizer and amorphizing agent, reaction temperature during the chemical sensitization and a combination of these various conditions.
As the method for amorphizing the chalcogen sensitization centers or gold chalcogen sensitization centers produced during the sensitization process, there are (1) a method of attaining amorphozation by allowing incorporation of other atoms or molecules into the sensitization centers during the formation of the sensitization centers, and (2) a method of attaining amorphozation by allowing adsorption of other atoms or molecules around the sensitization centers during the formation of the sensitization centers. Specifically, there is a method of performing the sensitization in the presence of atoms or molecules having a property of being incorporated into or adsorbed around the sensitization centers. In particular, the sensitization is preferably performed in the presence of at least one transition metal ion selected from those of Group IB, Group IIB, Group VIA, Group VIIA and Group VIII metals. A compound containing atoms or the like having the aforementioned property can be added as an amorphizing agent simultaneously with the addition of a sensitizer or before or after addition of the sensitizer. The aforementioned amorphizing agent may be an inorganic compound or an organic compound. Preferred amorphizing agents include a compound containing Group VIII transition metal ion (the metal ion is preferably derived from Pt, Pd, Ir, Ru, Fe etc., more preferably derived from Pt, Pd or Ir, further preferably derived from Pt or Pd, most preferably derived from Pt), a compound containing Group IB transition metal ion (Cu compound etc.), a compound containing Group IIB transition metal ion (Zn compound etc.), a compound containing Group VIA transition metal ion (Cr compound etc.) and a compound containing Group VIIA transition metal ion (Mn compound, Re compound etc.). Among these, a compound of a group VIII metal is preferred. As the adsorptive compound used in the aforementioned method of (2), there can be mentioned compounds that are likely to adsorb to silver halide or silver chalcogenide.
Since the aforementioned amorphizing agent shows different amorphizing action with respect to silver chalcogenide and gold silver chalcogenide depending on its type, addition method, addition amount, addition time and so forth, suitable addition conditions and suitable material can be selected by tracing the X-ray diffraction peak mentioned above. That is, the amorphization conditions can be determined based on crystallinity of silver chalcogenide (or gold silver chalcogenide) produced after mixing silver nitrate and chalcogen sensitizer (and gold sensitizer) in a model, and chemical sensitization can be controlled by performing the chalcogen sensitization using those conditions. In general, the amount of the amorphizing agent is preferably 10xe2x88x927 to 10xe2x88x924 (molar ratio) with respect to silver halide, or preferably {fraction (1/16)} to 16 times, more preferably xc2xc to 4 times, in a molar ratio with respect to a chalcogen sensitizer. Further, addition time of the amorphizing agent is also an important parameter for the amorphization, and it is preferably added within 10 minutes before or after the addition of the chalcogen sensitizer, more preferably within 5 minutes before or after the addition of the chalcogen sensitizer, particularly preferably within 2 minutes before or after the addition of the chalcogen sensitizer. Furthermore, in order to realize amorphization more effectively by the chemical sensitization method of the present invention, preferred is an embodiment utilizing a combination of the type of amorphizing agent, addition amount of amorphizing agent, addition amounts of chalcogen sensitizer and gold sensitizer, ratio of these, addition time of these (especially, timing of addition of the chalcogen sensitizer and the amorphizing agent), temperature of chemical sensitization and other chemical sensitization conditions explained above as preferred embodiments.
Of course, it is also possible to obtain intensity of the maximum peak of X-ray diffraction within the range defined in present invention by controlling conditions other than the addition of amorphizing agent, and the means for it is not limited to the addition of an amorphizing agent. In addition, although it is known to add some of the aforementioned compounds mentioned above as amorphizing agents at the time of chemical sensitization, the present invention provides a novel sensitization method for chalcogen sensitization or gold chalcogen sensitization, which has never been known, because the method of the present invention is a control method in which the chemical sensitization is optimized based on variation of peak intensity of X-ray diffraction of silver chalcogenide or gold silver chalcogenide serving as sensitization centers and used for the utterly first time, in contrast to conventional techniques in which the compounds are just simply added.
In the present invention, reduction sensitization can also be used in combination. For reduction sensitization, the reducing compounds disclosed in P. Grafkides, Chimie et Physique Photographique (Paul Montel, 1987, 5th edition), Research Disclosure, vol. 307, No. 307105 and so forth can be used. Specifically, there can be used aminoiminomethane-sulfinic acid (also known as thiourea dioxide), borane compounds (e.g., dimethylaminoborane), hydrazine compounds (e.g., hydrazine, p-tolylhydrazine), polyamine compounds (e.g., diethylenetriamine, triethylenetetramine), stannous chloride, silane compounds, reductones (e.g., ascorbic acid) sulfites, aldehydes, hydrogen gas and so forth. Reduction sensitization may also be performed in an atmosphere of high pH or excess silver ion (so-called silver ripening). Although reduction sensitization may be performed at any time during the preparation of silver halide grains, it is particularly preferably performed during the formation of silver halide grains. In the present invention, it is preferable to use an oxidizing agent for silver. Examples thereof include thiosulfonates (e.g., sodium benzenethiosulfonate), disulfide compounds (e.g., bis(4-acetanilidephenyl) disulfide, lipoic acid), iodine, mercury salts an so forth, and thiosulfonates and disulfide compounds are particularly preferred.
In the present invention, the chemical sensitization of silver halide is preferably performed in the presence of a silver halide solvent.
Specific examples of the silver halide solvent include thiocyanates (e.g., potassium thiocyanate), thioether compounds (e.g., the compounds described in U.S. Pat. Nos. 3,021,215, 3,271,157, JP-B-58-30571, JP-A-60-136736, in particular, 3,6-dithia-1,8-octanediol etc.), tetra-substituted thiourea compounds (e.g., the compounds described in JP-B-59-11892 and U.S. Pat. No. 4,221,863, in particular, tetramethylthiourea), thione compounds described in JP-B-60-1134, mercapto compounds described in JP-B-63-29727, mesoionic compounds described in JP-A-60-163042, selenoether compounds described in U.S. Pat. No. 4,782,013, telluroether compounds described in JP-A-2-118566 and sulfites. Among these, thiocyanates, thioether compounds, tetra-substituted thiourea compounds, thione compounds and mesoionic compounds are preferred. The amount of the silver halide solvent used is approximately from 10xe2x88x925 to 10xe2x88x922 mol per mol of silver halide.
Hereafter, various materials usable for the silver halide emulsion of the present invention and a silver halide photographic light-sensitive material (in some cases, merely referred to as light-sensitive material) that can be produced by using the silver halide emulsion of the present invention will be explained.
For the silver halide emulsion of the present invention, any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide and silver chloride can be used. Silver halide grains may have a regular crystal form such as a cubic or octahedral form, an irregular crystal form such as a spherical or tabular form, or a form that is a composite of these crystal forms. Further, mixtures of grains having various crystal forms can be used, but grains having regular crystal forms are preferably used.
The silver halide grains used in the present invention as final grains may have a multi-layer structure comprising two or more layers different in the iodide composition between the inside and the surface layer of the grains (e.g., internal high iodide grains or surface high iodide grains). They may also be grains in which latent image is mainly formed on surfaces thereof (e.g., negative emulsion) or grains in which the latent image is mainly formed in the inside of the grains (e.g., internal latent image-type emulsion, preliminarily fogged direct reversal-type emulsion). However, grains in which the latent image is mainly formed on the surfaces are preferred. For the silver halide emulsion of the present invention, tabular silver halide grains are preferably used. The silver halide emulsion of the present invention preferably contains, as the final grain form, tabular silver halide grains having an aspect ratio of 2 or more, more preferably tabular silver halide grains having an average aspect ratio of 6 or more, particularly preferably 8 or more. The tabular grain preferably has a diameter of 0.15-5.0 xcexcm (as a circle) and a thickness of 0.02-1.0 xcexcm, more preferably 0.03-0.5 xcexcm, particularly preferably 0.03-0.3 xcexcm. The average aspect ratio is obtained as an arithmetic average of the aspect ratios of individual grains determined at least for 100 silver halide grains.
The tabular grains as final grains may have a (111) plane or (100) plane as a main plane. In the case where the final grains have a regular crystal form or spherical form or a steric form, the diameter thereof is preferably 0.05-3 xcexcm, more preferably 0.08-2 xcexcm, and an emulsion showing monodispersion with a coefficient of variation of preferably 30% or less, more preferably 20% or less, particularly preferably 15% or less, is preferred. The structure and the production method of the monodispersed tabular grains are described in, for example, JP-A-63-151618. However, to state the form briefly here, 70% or more of the entire projected area of silver halide grains is occupied by tabular silver halide grains having a hexagonal shape with a ratio of the length of a side having a maximum length to the length of a side having a minimum length being 2 or less and having two parallel planes as the outer surfaces, and the tabular grains are those showing monodispersion with a coefficient of variation [a value obtained by dividing the variation (standard deviation) of grain sizes represented by a diameter of a circle having the same area as the projected area of a grain with the average grain size] in the grain size distribution of the hexagonal tabular silver halide grains of 30% or less, preferably 20% or less, more preferably 15% or less.
In the present invention, the tabular grains as final grains preferably have dislocation lines. The dislocation lines of the tabular grain can be observed by a direct method using a transmission-type electron microscope at a low temperature as described in, for example, J. F. Hamilton, Phot. Sci. Eng., 11, 57 (1967) and T. Shiozawa, J. Soc. Phot. Sci. Japan, 35, 213 (1972). The dislocation lines may be blade-like dislocations or screw dislocations. Each grain preferably has at least 5 dislocation lines, more preferably 10 dislocation lines. Further, it preferably has a portion formed by epitaxial growth.
Further, during grain formation of the silver halide grains, there can be used a silver halide solvent for controlling the grain growth, for example, ammonia, potassium thiocyanate, ammonium thiocyanate, thioether compounds (e.g., those disclosed in U.S. Pat. Nos. 3,271,157, 3,574,628, 3,704,130, 4,297,439, 4,276,374), thione compounds (e.g., those disclosed in JP-A-53-144319, JP-A-53-82408, JP-A-55-77737) and amine compounds (e.g., those disclosed in JP-A-54-100717).
During the formation of silver halide grains or physical ripening thereof, a ruthenium salt (e.g., hexacyanoruthenium), zinc salt, chromium salt, iridium salt or complex salt thereof (e.g., iridium hexachloride, aquoiridium pentachloride, thiazole iridium pentachloride), rhodium salt or complex salt thereof (e.g., rhodium hexachloride, rhodium aquorhodium), or iron salt or iron complex salt (e.g., yellow prussiate of potash) may be present together. Among these, an iridium salt, iron salt and rhodium salt are preferred. A hexa-coordinate compound is particularly preferred.
The silver halide emulsion of the present invention preferably contains a hydrophilic polymer as a binder for forming a layer and/or protective colloid. Examples of the hydrophilic polymer include proteins such as gelatin derivatives, graft polymers of gelatin with other polymers, albumin and casein; saccharide derivatives such as cellulose derivatives (e.g., hydroxyethylcellulose, carboxymethylcellulose, cellulose sulfate), sodium alginate and starch derivatives; and various synthetic hydrophilic polymers including homopolymers and copolymers such as polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinyl-pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole or polyvinylpyrazole. Among the aforementioned hydrophilic polymers, gelatin is preferred. As gelatin, besides commonly used lime-treated gelatin, acid gelatin and acid-treated gelatin described in Bull. Soc. Phot. Japan, No. 16, p. 30, (1966) may also be used, and hydrolysate of gelatin can also be used.
The aforementioned hydrophilic polymer can be used not only for an emulsion layer but also for an intermediate layer of a photographic light-sensitive material.
The silver halide photographic emulsion of the present invention is preferably spectrally sensitized with a methine dye or others. Examples of the dye used include a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a hemicyanine dye, a styryl dye and a hemioxonol dye. Among these, preferred are dyes belonging to the cyanine dye, merocyanine dye or complex merocyanine dye. For these dyes, any nucleus commonly used for cyanine dyes as a basic heterocyclic nucleus can be used. Examples of the nucleus include pyrroline nucleus, oxazoline nucleus, thiazoline nucleus, pyrrol nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus, imidazole nucleus, tetrazole nucleus and pyridine nucleus; nuclei resulting from fusion of an alicyclic hydrocarbon ring to the aforementioned nuclei; and nuclei resulting from fusion of an aromatic hydrocarbon ring to the aforementioned nuclei, e.g., indolenine nucleus, benzindolenine nucleus, indole nucleus, benzoxazole nucleus, naphthooxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, benzoselenazole nucleus, benzimidazole nucleus, quinoline nucleus and so forth. These nuclei may have a substituent on a carbon atom. For the merocyanine dye or complex merocyanine dye, a 5- or 6-membered heterocyclic nucleus such as pyrazolin-5-one nucleus, thiohydantoin nucleus, 2-thiooxazolidine-2,4-dione nucleus, thiazolidine-2,4-dione nucleus, rhodanine nucleus and thiobarbituric acid nucleus may be used as a nucleus having a ketomethylene structure.
These sensitizing dyes may be used each alone or in combination. A combination of sensitizing dyes is often used for the purpose of supersensitization. Further, dyes that themselves do not have a spectral sensitization action or materials that substantially do not absorb visible light but show supersensitization can be incorporated into the emulsion together with sensitizing dyes. For example, substituted aminostilbene compounds substituted with a nitrogen-containing heterocyclic nucleus group (e.g., those disclosed in U.S. Pat. Nos. 2,933,390 and 3,635,721), aromatic organic acid-formaldehyde condensates (those disclosed in U.S. Pat. No. 3,743,510), cadmium salts or azaindene compounds and so forth may be contained in the emulsion. The combinations disclosed in U.S. Pat. Nos. 3,615,613, 3,615,641, 3,617,295 and 3,635,721 are particularly effective.
Various compounds can be added to the silver halide photographic emulsion of the present invention for preventing generation of fog, stabilizing photographic performances or the like during production or storage of the light-sensitive material. Such compounds include compounds known as antifoggants or stabilizers such as azoles, e.g., benzothiazolium salts, nitroimidazole salts, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (in particular, 1-phenyl-5-mercaptotetrazoles); mercaptopyrimidines; mercaptotriazines; thioketo compounds, e.g., oxazolinethione; azaindenes, e.g., triazaindenes, tetrazaindenes (in particular, 4-hydroxy-6-methyl (1,3,3a,7)tetrazaindene), pentaazaindenes; benzenethiosulfinic acid, and benzenesulfonic acid amide.
The silver halide emulsion of the present invention (in particular, emulsion comprising tabular grains) can be prepared according to the methods disclosed in Cleve, Photography Theory and Practice, page 131 (1930); Gutoff, Photographic Science and Engineering, Vol. 14, pages 248 to 257 (1970), U.S. Pat. Nos. 4,434,226, 4,414,310, 4,433,048, 4,439,520, British Patent No. 2,112,157 and so forth.
A silver halide photographic light-sensitive material can be produced by using the silver halide emulsion of the present invention. The light-sensitive material has a photosensitive layer containing the silver halide emulsion of the present invention on a support, for example. In addition to the aforementioned photosensitive layer, it may have a back layer, intermediate layer, protective layer and so forth, and it may have two or more photosensitive layers.
The photographic light-sensitive material may contain an inorganic or organic hardening agent in any hydrophilic colloid layer constituting the photographic light-sensitive layer or back layer. Specific examples thereof include chromium salts, aldehyde salts (e.g., formaldehyde, glyoxal, glutaraldehyde) and N-methylol type compounds (e.g., dimethylolurea). Further, active halogen compounds (e.g., 2,4-dichloro-6-hydroxy-1,3,5-triazine and a sodium salt thereof) and active vinyl compounds (e.g., 1,3-bisvinylsulfonyl-2-propanol, 1,2-bis(vinylsulfonylacetamide)ethane, bis(vinylsulfonylmethyl) ether, vinyl polymers having a vinylsulfonyl group on side chains thereof) are preferred because they can rapidly harden the hydrophilic colloid such as gelatin to provide stable photographic properties. Furthermore, N-carbamoylpyridinium salts (e.g., (1-morpholinocarbonyl-3-pyridinio)methanesulfonate) and haloamidinium salts (e.g., 1- (1-chloro-1-pyridinomethylene)pyrrolidinium-2-naphthalenesulfonate) also have a superior effect of realizing rapid hardening.
The light-sensitive material may contain one or more surface active agents for various purposes, for example, as a coating aid or antistatic agent or for improving lubricity, emulsion dispersion, preventing adhesion, improving photographic properties (e.g., development acceleration, increase of contrast, sensitization) and so forth in the same layer as the aforementioned silver halide emulsion layer or another layer.
The light-sensitive material may have a hydrophilic colloid layer for preventing irradiation or halation. A water-soluble dye can be added to the hydrophilic colloid layer as a filter dye. Preferred examples of such a dye include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, anthraquinone dyes and azo dyes. Other than these dyes, cyanine dyes, azomethine dyes, triarylmethane dyes and phthalocyanine dyes are also useful. It is also possible to emulsify an oil-soluble dye by the oil-in-water dispersion method and add it to the hydrophilic colloid layer.
The light-sensitive material may be constructed as a multi-layer multicolor photographic light-sensitive material having at least two different spectral sensitivities on a support.
Such a multi-layer natural color photographic material usually has at least one red-sensitive emulsion layer, at least one green-sensitive emulsion layer and at least one blue-sensitive emulsion layer on the support. The arrangement order of these layers may be freely selected according to the purpose. Preferred arrangements include the order of a red-sensitive layer, a green-sensitive layer and a blue-sensitive layer from the support side, the order of a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer from the support side, and the order of a blue-sensitive layer, a red-sensitive layer and a green-sensitive layer from the support side. Further, any emulsion layer having the same color sensitivity may be constituted by two or more emulsion layers different in the sensitivity to increase the ultimate sensitivity. A three-layer structure may also be used to further improve the graininess. Furthermore, an emulsion layer having different color sensitivity may be interposed between the emulsion layers having the same color sensitivity. Still further, a reflection layer containing fine grain silver halide or the like may be provided under a high sensitivity layer, in particular, under a high sensitivity blue-sensitive layer, to increase the sensitivity.
The additives used in the silver halide emulsion of the present invention are described in Research Disclosure, Nos. 17643, 18716 and 307105, and the pertinent portions are summarized in the table mentioned below.
Other techniques and inorganic or organic materials which can be used in the photographic light-sensitive material of the present invention are described in the following portions of European Unexamined Patent Publication No. 436938A2 or in the patents mentioned below.
Layer structure: from p. 146, line 34 to p. 147, line 25
Yellow coupler: from p. 137, line 35 to p. 146, line 33, and p. 149, lines 21 to 23
Magenta coupler: from p. 149, lines 24 to 28: and from p. 3, line 5 to p. 25, line 55 of European Unexamined Patent Publication No. 421453A1
Cyan coupler: from p. 149, lines 29 to 33; and from p. 3, line 28 to p. 40, line 2 of European Unexamined Patent Publication No. 432804A2
Polymer coupler: p. 149, lines 34 to 38; and from p. 113, line 39 to p. 123, line 37 of European Unexamined Patent Publication No. 435334A2
Colored coupler: from p. 53, line 42 to p. 137, line 34, and p. 149, lines 39 to 45
Other functional couplers: from p. 7, line 1 to p. 53, line 41, and p. 149, line 46 to p. 150, line 3; and from p. 3, line 1 to p. 29, line 50 of European Unexamined Patent Publication No. 435334A2
Antiseptic and insecticide: p. 150, lines 25 to 28
Formalin scavenger: p. 149, lines 15 to 17
Other additives: p. 153, lines 38 to 47; and from p. 75, line 21 to p. 84, line 56, and from p. 27, line 40 to p. 37, line 40 of European Unexamined Patent Publication No. 421453A1
Dispersion method: p. 150, lines 4 to 24
Support: p. 150, lines 32 to 34
Thickness and physical properties of layers: p. 150, lines 35 to 49
Color development process: p. 150, line 50 to p. 151, line 47
Desilvering process: p. 151, line 48 to p. 152, line 53
Automatic developing machine: p. 152, line 54 to p. 153, line 2
Water washing and stabilization processes: p. 153, lines 3 to 37
The present invention can be applied to various color or black-and-white photographic materials. Representative examples thereof include color negative film for general purpose or movies, color reversal film for slide or television, color paper, color positive film and color reversal paper, a color diffusion transfer type photosensitive material and a color photothermographic material. By using a tricolor coupler mixture described in Research Disclosure, No. 17123 (July, 1978) or a black color-forming coupler described in U.S. Pat. No. 4,126,461 and British Patent No. 2,102,136, the present invention can be applied also to a black-and-white photographic material such as X-ray film. Further, the present invention can be applied to film for platemaking such as lith film or scanner film, X-ray film for direct or indirect medical use or industrial use, negative black-and-white film for photographing, black-and-white printing paper, microfilm for COM or general use, a silver salt diffusion transfer type photosensitive material or a print-out type photosensitive material.
Preferred embodiments of the present invention are mentioned below.
(1) A silver halide emulsion containing silver chalcogenide or gold silver chalcogenide produced by chemical sensitization, wherein at least a part of the silver chalcogenide or gold silver chalcogenide is amorphous.
(2) The silver halide emulsion according to (1), wherein intensity of a maximum X-ray diffraction peak of the silver chalcogenide or gold silver chalcogenide is xc2xd or less of intensity of a maximum X-ray diffraction peak of silver chalcogenide or gold silver chalcogenide that is not amorphized.
(3) A silver halide emulsion according to (1) or (2), wherein a maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained by applying the conditions of the chemical sensitization to a simplified model as defined in the following (b) (Intensity B) and a maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained for a standard model as defined in the following (a) (Intensity A) satisfy the relational equation defined in the following (c):
(a) silver chalcogenide or gold silver chalcogenide produced by mixing 20 mL of 0.01 mol/L silver nitrate aqueous solution, 20 mL of 0.01 mol/L solution of the chalcogen compound in water or an alcohol and, when a gold compound is also used in the chemical sensitization, 0.01 mol/L solution of the gold compound in water or an alcohol in such an amount that the gold compound and the chalcogen compound should exist in the same molar ratio as that used for the chemical sensitization at the temperature used for the chemical sensitization,
(b) silver chalcogenide or gold silver chalcogenide produced by mixing the chalcogen compound or the chalcogen compound and the gold compound with 20 mL of 0.01 mol/L silver nitrate aqueous solution under the same conditions as those of the chemical sensitization, except that the silver halide emulsion does not exist, the chalcogen compound is added as 0.01 mol/L solution in water or an alcohol and the other additives are added in such amounts that molar ratios of the additives with respect to the chalcogen compound should be the same molar ratios as those used for the chemical sensitization,
(c) B/Axe2x89xa6xc2xd.
(4) A method for chemical sensitization of a silver halide emulsion comprising a sensitization step of subjecting the silver halide emulsion to chemical sensitization with a chalcogen compound or a chalcogen compound and a gold compound to produce silver chalcogenide or gold silver chalcogenide, wherein the chemical sensitization is performed under such conditions that at least a part of the silver chalcogenide or gold silver chalcogenide produced in the sensitization step should be amorphized.
(5) The method for chemical sensitization of a silver halide emulsion according to (4), wherein an amorphizing agent is used in the sensitization step.
(6) The method for chemical sensitization of a silver halide emulsion according to (4) or (5), wherein the chemical sensitization is performed in the presence of transition metal ions of at least one metal selected from the metals of Group IB, Group IIB, Group VIA, Group VIIA and Group VIII.
(7) The method for chemical sensitization of a silver halide emulsion according to any one of (4) to (6), wherein a maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained for a standard model as defined in the following (a) (Intensity A) and a maximum X-ray diffraction peak intensity of silver chalcogenide or gold silver chalcogenide obtained by applying the chemical sensitization conditions of the sensitization step to a simplified model as defined in the following (b) (Intensity B) satisfy the relational equation defined in the following (c):
(a) silver chalcogenide or gold silver chalcogenide produced by mixing 20 mL of 0.01 mol/L silver nitrate aqueous solution, 20 mL of 0.01 mol/L solution of the chalcogen compound in water or an alcohol and, when a gold compound is also used in the chemical sensitization, 0.01 mol/L solution of the gold compound in water or an alcohol in such an amount that the gold compound and the chalcogen compound should exist in the same molar ratio as that used for the chemical sensitization at the temperature used for the chemical sensitization,
(b) silver chalcogenide or gold silver chalcogenide produced by mixing the chalcogen compound or the chalcogen compound and the gold compound with 20 mL of 0.01 mol/L silver nitrate aqueous solution under the same conditions as those of the chemical sensitization, except that the silver halide emulsion does not exist, the chalcogen compound is added as 0.01 mol/L solution in water or an alcohol and the other additives are added in such amounts that molar ratios of the additives with respect to the chalcogen compound should be the same molar ratios as those used for the chemical sensitization,
(c) B/Axe2x89xa6xc2xd.
(8) The silver halide emulsion according to any one of (1) to (3) or the method for chemical sensitization of an silver halide emulsion according to any one of (4) to (7), wherein a gold sensitizer (especially a gold sensitizer having an organic ligand) is used in the sensitization step.
(9) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein reduction sensitization is used in combination in the sensitization step, especially during formation of silver halide grains.
(10) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein a sensitizing dye (preferably amelocyanine dye or cyanine dye, particularly preferably a cyanine dye) is added during the sensitization step or before or after the sensitization step.
(11) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein a nitrogen-containing heterocyclic compound, especially a heterocyclic compound containing two or more nitrogen atoms, is added during the sensitization step.
(12) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the silver halide grains are tabular grains having an aspect ratio of 2 or more, preferably 6 or more, particularly preferably 8 or more.
(13) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the tabular grains mentioned in (12) have a (111) plane as a main plane.
(14) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the tabular grains mentioned in (12) have a (100) plane as a main plane.
(15) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the silver halide grains have dislocation lines, in particular, 5 or more lines per one grain.
(16) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the silver halide grains have a portion formed by epitaxial growth.
(17) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the silver halide grains have a coefficient of variation of 30% or less, preferably 20% or less, particularly preferably 15% or less, for the grain size.
(18) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein the silver halide grains contain a Group VIII metal (e.g., Fe, Ir, Ru, Rh, Os etc.) or an inorganic or organic hexa-coordinate complex thereof.
(19) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, which contains at least one of the compounds disclosed in U.S. Pat. Nos. 5,413,905, 5,482,825, 5,747,235, 5,747,236, 5,994,051 and 6,054,260.
(20) The silver halide emulsion or the method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein a compound of Group VIII metal (especially Pt) is added as an amorphizing agent within 5 minute before or after addition of the chalcogen compound in an amount of 1/16 to 16 times the amount of the chalcogen compound.
(21) The silver halide emulsion or method for chemical sensitization of a silver halide emulsion according to any one of the aforementioned embodiments, wherein a compound of Group VIII metal (especially Pt) is added as an amorphizing agent within 2 minute before or after addition of the chalcogen compound in an amount of xc2xc to 4 times the amount of the chalcogen compound.
(22) A silver halide photographic light-sensitive material containing any one of the aforementioned silver halide emulsions.